Device for the uniform application of small amounts of a powdery material onto surface configurations

ABSTRACT

Apparatus for depositing particulate material onto a textile fabric, particularly thermoplastic adhesive particles onto a nonwoven substantially continuous fabric, including means for depositing the particulate material onto a feeder disc with an inwardly directed spiral bead thereon and an aperture in the center thereof, a centrifugal spreader disc disposed beneath the feeder disc, means for, rotating the discs, and means for passing the fabric beneath the spreader disc whereby only part of the annular centrifuged particles are deposited on the textile fabric.

United States Patent Brehm Mar. 21, 1972 541 DEVICE FOR THE UNIFORM 1561 References it d APPLICATION OF sMALL AMOUNTS UNITED STATES PATENTS OF A POWDERY MATERIAL ONTO 2,804,309 8/1957 Sweet ..239/687 SURFACE CONFIGURATIONS 2,962,381 11/1960 Dobry et al... ....1 17/16 72 l t I H B h F th Odenwald, German 2,993,309 7/1961 Barnes et a1. 1 17/16 1 or ans N net I y 3,014,812 12/1961 'Sallie ..117/24 [73] Assignee: Carl Freudenberg, Weinheim/Bergstrasse, 3,342,415 9/1967 Point 239/223 Germany 3,478,969 11/1969 Lund ..117/16 [22] Filed: 1969 Primary Examiner--William D. Martin [21] App1.No.: 848,505 Assistant ExaminerRaymond M. Speer Attorney-Burgess, Dinklage & Sprung [30] Foreign Application Priority Data 57 ABSTRACT P 1969 Germany 19 13 033-7 Apparatus for depositing particulate material onto a textile fabric, particularly thermoplastic adhesive particles onto a [52] U.S.Cl ..118/308, 1 17/ 16, 117/21, non-woven substantially continuous fabric, including means 117/24, 1 17/ 104, 118/325 for depositing the particulate material onto a feeder disc with [51] Int. Cl ..BOSb 7/14 an inwardly directed spiral bead thereon and an aperture in [58] Field of Search ..1 17/16, 21, 24, 33, 104,122; the center thereof, a centrifugal pr disc disposed 113 230 303 313; 239/223 224 656 7 673 beneath the feeder disc, means for, rotating the discs, and 682, 687 means for passing the fabric beneath the spreader disc whereby only part of the annular centrifuged particles are deposited on the textile fabric. 15

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DEVICE FOR THE UNIFORM APPLICATION OF SMALL AMOUNTS OF A POWDERY MATERIAL ONTO SURFACE CONFIGURATIONS For many purposes it is necessary to apply by powdering or dusting a powdery material in very small amounts, e.g., to 30 g./sq.m., as uniformly as possible over an area. In particular, the manufacture of iron-on stiffening material according to the DAS 1,096,324 uses this type of operation. In that case, polyethylene powder is spread onto a fabric or a fleece. Then, the temperature was increased until the polyethylene grains were superficially softened. The grains are then permanently sintered onto the base fabric or fleece. Such a stiffening material can be joined to another fabric by placing its polyethylene containing side juxtaposed the other material to be reinforced and passing a hot iron over the back (nonpolyethylene containing) side of the stiffening material. In the process, the polyethylene particles will soften once again and thus produce a firm bond between the two materials.

It is understood that in the manufacture of such stiffening materials as well as in many other instances, it is desirable to achieve as uniform an application of polyethylene or other particulate adhesive grains as possible. If the polyethylene would be applied, for instance, with an ordinary saltshaker, the distribution thereof would of course be very uneven. This, in turn, would result in points with an overconcentration whereat the polyethylene would, the moment the hot iron passes over it, penetrate into the upper material and even penetrate through it to its back side (face) whereby producing a greasy spot on the face of the material at that point. At locations where there is only a small amount ofor no polyethylene, the bondings between the two fabrics is, or may be, inadequate. A delamination of the reinforcing and other layer or layers sometimes occurs in the areas of deficient polyethylene concentration.

It is particularly difficult to obtain uniform distribution of the thermoplastic adhesive grains in those cases in which only very small amounts of grain are to be applied, e.g., 5g./sq.m. In these cases, each grain is, for all practical purposes, separated from the other ones. However, satisfactory ironing requires that the distance from grain to grain be as uniform as possible.

This problem of uniform distribution just described has been overcome by the apparatus of the instant invention, which comprises means for depositing the particulate coating material onto a feeder disc with an inwardly directed spiral bead thereon and an aperture in the center thereof, a centrifugal spreader disc disposed beneath the feeder disc, means for rotating the discs, and means for passing a textile fabric beneath the spreader disc whereby only part of the annular centrifuged particles are deposited on the textile fabric.

In the drawingappended to the instant specification and constituting a part hereof several views are shown as follows:

FIG. I is a prospective view of a slot powder deposition means.

FIG. 2 is a partial sectioned end view of the slot deposition means of FIG. 1.

FIG. 3 shows an end view of centrifugal spreader disc.

FIG. 4 is similar to FIG. 3, showing the spreader disc in operation.

FIG. 5 is a plan view of particulate material spread between spreader disc of FIG. 4.

FIG. 6 is an end view of a spreader disc assembly.

FIG. 7 is a plan view of the particulate material spread as shown in FIG. 6.

FIG. 8 is similar to FIG. 6 but showing a more complicated spreader disc arrangement.

FIG. 9 is a plan view of an annular ring of a particulate material disposed on one of the intermediate spreader disc of FIG. 8.

FIG. 10 is a prospective view of a feeding means.

FIG. 1 1 is a prospective view of the entire apparatus of this invention.

The prior art procedure usually used for the uniform application of granular material on endless webs, was to place the powder into an elongated vibrator trough as shown in FIGS. 1

and 2, and vibrating the trough by means of a mechanism (not shown), which would cause powder to pour out of the slot 2 in the bottom of the trough onto a web of fabric or fleece material situated therebeneath and running at a uniform rate from left to right (or vice versa).

Many thermoplastic adhesive powders are known to tend to agglomerate. There are then formed large lumps in the initially fine-grained powders in the vibrator trough, which are no longer able to pass through the narrow slot. Thus, the slot is, in part, blocked and the web passing therebeneath does not receive any powder coating whatsoever in the areas corresponding to these blockage points. It is known to be possible to break up such lumps with a thin wire that is pressed, from the top, against the lumps situated in the trough over the slot 2; however, this action tends to, at least temporarily, cause an excessive amount of powder to be deposited on the web situated therebeneath.

According to the instant invention, these drawbacks can be obviated. This is achieved by means of distributor discs hereinafter described in greater detail.

For the purpose of a better comprehension of the invention, reference is had to the per se known vehicles used in the winter period for sandspreading icy roads. Only a few years ago it used to be customary to load a truck with sand. While the truck was travelling on the icy road, two men would then throw shovelfuls of sand from the moving truck onto the road. In recent years, increasing preference has been given to spreader vehicles equipped with a rapidly rotating disc at the end of the vehicle. The workers now shovel the sand no longer directly onto the road, but onto the rapidly rotating disc. From there, the sand grains are then, by centrifugal force, flung over the entire roadway. One thereby achieves a uniform distribution of the sand on the road. In view of the fact that, in addition, overconcentrations could be avoided (at the points at which a shovelful of sand dropped on the road there was naturally more sand than the amount absolutely necessary for eliminating the skidding hazard) it was also possible to save sand.

However, it is not possible to make a direct transposition of the spreader process just described to the uniform application of small amounts of powder onto an endless web. It would require excessive cost with regard to devices and structures in order to lay out a web of material of substantial length in a building and then to allow the spreader disc, which, in addition would have to be provided with a feeder device to be replenished with fresh powder, to glide over the entire length of the web of perhaps meters. Even if it would be possible thus to apply the plastic powder uniformly onto the web, there arises the problem of additional processing. After all, initially, the powder lies only loosely uniformly distributed on the web. If the web would now be actuated in order to bring it into a hot air chamber for fixing the powder by means of sintering, the uniform arrangement of the powder would be destroyed as a result of the shaking motion during transport.

Now, the present invention obviates all of these drawbacks by a reversal of the spreader disc principle. If it has been the case, in the past, that a movable spreader disc was gliding over a web in movement, the very contrary is true in the case of the invention. The endless web to be powdered passes under a fixedly mounted spreader disc. This principle is to be explained by means of FIGS. 3 to 11.

FIG. 3 shows a spreader disc 4 capable of rotation around the shaft 3. If granular material is applied to the disc 4, without rotation of the disc, said material will of course first remain lying on the disc.

However, if the spreader disc 4 starts to rotate, as can be seen in FIG. 4, the powder 6 is, as can be expected, flung by centrifugal force over the edges of the disc 4 and drops then onto the table 5. The distribution pattern will then be present substantially in the shape of a wide ring, as can be seen in FIG. 5.

If a web is situated on the table 5, the powder will then naturally lie in an annular shape on said web.

It will of course be understood that a web cannot be homogeneously and uniformly powdered by means of the aforementioned technique. This is possible only when the web to be powdered is put into motion at a uniform rate. It is furthermore important that the table, or the web thereon, should be sufficiently narrow so that the grains flung off from the disc 4 will extend sideways a distance sufficient so that they will pass the left, or the right edge of the table as shown in FIG. 6. At those points there are arranged deflector plates 7 and 8 allowing the grains flung off over the right and left table edge to glide into collector means 9 and 10.

It is to be noted that the table, or the web thereon, is very long in the direction toward or away from the viewer in FIG. 6.

If a spreader disc throws powder onto such a table, a closed ring will no longer be formed, because a part of the powder will pass too far to the right and to the left and will drop" over the table. On the table there will then remain only the arc-shaped segments 11 and 12 shown hatched in FIG. 7.

If the continuous web a moves across the table in the direction of the arrow in FIG. 7 and if the disc 4 continuously flings off powder 6, the web will pass uninterruptedly through the two rain regions 11 and 12. The grains will drop uniformly distributed within the zones 11 and 12, and therefore downstream of the zone 11 will also consequently exhibit an extremely uniform application of grains. The web can then be passed through a heating chamber preferably as soon as possible, where the particles are softened and affixed by sintering onto the carrier web. The initially uniform application of the grains cannot be disturbed after sintering, and is not disturbed in the short transit between spreading and sintering of the grains. Such a disturbance would occur only if the web would have to run over a very long period prior to the fixing of the grain particles.

A uniform and constant delivery of particles within the zones II and 12 requires as a prerequisite, a uniform feeding of powder onto the spreader disc 4. This is achieved in accordance with the invention by not directly applying onto the spreader disc 4. Rather, auxiliary additional spreader discs are used, as can be seen in FIG. 8.

The powder thus drops out of a standard vibrator trough 13 into a conduit 14 and from there onto a first rotating spreader disc 15, from there onto the likewise rotating second spreader disc 16 which is wider than the first spreader disc and from there onto the principal spreader disc 4 from which the grains are finally spread onto the web in motion therebeneath, according to this invention, as described above in connection with FIGS. 3 to 7. The primary and secondary discs 15 and 16 are respectively surrounded, at a distance of a few centimeters about their entire circumferences, by deflector plates 15a and 16b. The powder grains first applied to the primary disc 15 are then, due to the centrifugal force, flung against the deflector plate 15a and dropped from there onto the secondary disc 16. Whereas the powder coming out of the conduit 14 may, for all practical purposes, still fall on any part of the primary disc 15, the grains which fall from the primary disc 15 onto disc 16 fall in an annular ring as shown in FIG. 9. Those parts that are situated directly beneath the primary disc 15 remain practically free of any powder grains. If the secondary disc 16, in turn, did not rotate, the powder falling down thereonto from the plate 15a would collect thereon in the form of a very narrow ring 17 as shown in FIG. 9. From there upon rotation of the secondary disc 16, the powder grains are flung over its edge and against the deflector plate 16b from which the powder grains-once again in the form of a round bandfall onto the principal spreader disc 4, also illustrated by the configuration of FIG. 9. Because the round strip of powder grains on this disc 4 is now already very uniform with respect to its width and distribution of powder grains therein, a high degree of uniformity of distribution of powder grains is achieved within the segments 11 and 12 (ofFlG. 7).

In view of the fact that the webs 5a to be powdered are, in practice, very wide, e.g., l to 2 meters, the segments 11 and 12 will have substantially no arc therein. The two deposition zones 1 1 and 12 will be substantially rectangular.

Still greater uniformity in powder distribution on the web 5d can be achieved if the powder is allowed to drop first onto a slowly rotating disc 18 provided in its center with a large opening 21, as can be seen in FIG. 10. Onto this disc 18 there has loosely been mounted a bead 19. This bead 19 is spiral shaped with one single spiral winding being present within 360 C. One end of the spiral 19 terminates at the edge of the hole 21 in the disc and the other at the outer edge of the disc 18.

Powder falls from a hopper 20 onto the disc 18 rotating in the direction of the arrow (i.e., clockwise). The bead 19 does not rotate with the disc 18 but rather is stationary whereby guiding the powder grains from the hopper 20 toward the hole 21.

The powder dropping out of the end of the hopper onto the disc 18 rotates with the disc. As the disc 18 rotates, the powder is pressed more and more against the wall of the bead 19 while at the same time, excess powder that has no more space on the increasingly smaller strip is pressed over the edge of the hole and drops from there onto the discs situated therebeneath where, due to centrifugal force in the manner described above, it will via a plurality of discs 15, 16 and 4, finally fall onto the web in the form of two strips 11 and 12. The disc 18 rotates extremely slowly (preferred circumferential speed 10 m./min.) so that, substantially no noticeable centrifugal force is applied to the powder grains falling through the hole 21. The discs 15, 16, and 4 rotate about 30 times faster than the disc 18.

FIG. 11 schematically illustrates the entire preferred embodiment of this invention permitting maximum uniformity of grain deposition.

Out of the hopper 20 granular material falls uniformly onto the disc 18. The powder drops through the hole 21 in the slowly rotating disc 18 in the form of a narrowannular'band first onto the primary disc 15 from which it is flung against the deflector plate (not shown), and then falls from there onto the secondary disc 16 and from which it is flung from there, again in the shape of a circular band 21, onto the web 5a running over the table 5 in the direction of the arrow. The principal spreader disc 4 is omitted from FIG. 1 l for simplicity and clarity purposes.

For the purpose of clarifying the relationships FIG. 11 shows the web 5a not running during production of the circular strip of grains 21. The bands of grains 21a and 21b are illustrated as if the web 5 was moved out in the direction of the arrow, from under the spreader 16. These bands 21a and 21b correspond to the segments 11 and 12 in FIG. 7.

The grain particles being spread to the right and to the left beyond the width of the web are deliberately cast away in the process according to the application. These powder portions can be collected again in the manner illustrated in FIG. 8 and then reused by placing them in the hopper 20.

What is claimed is:

1. Apparatus for applying particulate material to a substantially continuous textile fabric comprising: feed and takeup means for said textile fabric and textile fabric disposed therebetween; centrifugal spreader means assembly disposed above said textile fabric between said feed and takeup means; motive means operatively connected to said spreader means assembly to impart rotation thereto; feed means disposed above said spreader means assembly for depositing particulate material to be spread on said spreader means assembly, wherein said spreader means assembly includes at least one spreader disc, a distributor disc having at its center an aperture therein disposed above said spreader disc and a substantially stationary spiral bead means on said distributor disc for directing particulate material deposited on said distributor disc toward and through said aperture wherein said feed means is positioned to feed particulate material onto said distributor disc and said distributor disc feeds particulate material through said aperture onto said spreader disc, wherein the speed of rotation of said spreader disc and the maximum diameter of said spreader disc are suflicient to cause said particulate material to be centrifuged off said spreader disc in an annular pattern onto said textile fabric which annular pattern has an inside diameter which is larger than the width of said deflector means disposed about all of said spreader discs extextile fabric. cept the spreader disc closest to said fabric.

PP as claimed in clam including multiple 4. Apparatus as claimed in claim 2, wherein said spreader spreader discs substantially parallel to each other of increasing diameter toward said textile fabric.

3. Apparatus as claimed in claim 2, including peripheral discs have a common axial drive shaft. 

1. Apparatus for applying particulate material to a substantially continuous textile fabric comprising: feed and takeup means for said textile fabric and textile fabric disposed therebetween; centrifugal spreader means assembly disposed above said textile fabric between said feed and takeup means; motive means operatively connected to said spreader means assembly to impart rotation thereto; feed means disposed above said spreader means assembly for depositing particulate material to be spread on said spreader means assembly, wherein said spreader means assembly includes at least one spreader disc, a distributor disc having at its center an aperture therein disposed above said spreader disc and a substantially stationary spiral bead means on said distributor disc for directing particulate material deposited on said distributor disc toward and through said aperture wherein said feed means is positioned to feed particulate material onto said distributor disc and said distributor disc feeds particulate material through said aperture onto said spreader disc, wherein the speed of rotation of said spreader disc and the maximum diameter of said spreader disc are sufficient to cause said particulate material to be centrifuged off said spreader disc in an annular pattern onto said textile fabric which annular pattern has an inside diameter which is larger than the width of said textile fabric.
 2. Apparatus as claimed in claim 1, including multiple spreader discs substantially parallel to each other of increasing diameter toward said textile fabric.
 3. Apparatus as claimed in claim 2, including peripheral deflector means disposed about all of said spreader discs except the spreader disc closest to said fabric.
 4. Apparatus as claimed in claim 2, wherein said spreader discs have a common axial drive shaft. 